1. Field of the Invention
The present invention relates to dentistry equipment, and, in particular, to sleeves for rotary dental instruments, such as those for treating tooth cavities.
2. Description of the Related Art
Instruments used in dental surgery require absolute hygiene which obliges dentists to regularly clean and disinfect the instruments. This repeated cleaning and disinfecting can actually damage the sleeves that are often part of rotary dental instruments. In particular, aluminum sleeves may be attacked by the disinfectants, and plastic sleeves may swell under the effect of formaline, which is often used as a disinfectant.
To overcome these drawbacks, French patent 2 499 446 describes a mixed sleeve, namely one that is not solely made of plastic, which enables the sleeve to be less sensitive to cleaning or disinfecting. Nevertheless, the sleeve described in the patent has some drawbacks. In particular, the patent describes anchoring means in the form of a perforation or opening in a cylindrical metal tube where plastic material projects into that opening. Such anchoring means have the drawback that, when the user cleans and/or disinfects the instrument with products that cause plastic to swell, the plastic material in the sleeve will protrude slightly from the outer surface of the cylindrical metal tube and thereby form a projection that may make it difficult to place the instrument in the hand-piece.
Moreover, application of the invention of French patent 2 499 446 to certain types of dental instruments would require a redesign of how the cylindrical metal tube is manufactured which would cause the manufacturing process to be more expensive.
The present invention addresses the drawbacks of the devices of the prior art as described above. Aspects and advantages of this invention will become apparent from the detailed description which follows.